3D Mammograms Reduce Risk of Advanced-Stage Disease in Women With Extremely Dense Breasts and High Risk of Breast Cancer
In women with extremely dense breasts and a high risk of breast cancer, screening with 3D mammograms — rather than 2D digital mammograms — was linked to a lower risk of advanced-stage disease, according to a study.
The research was published on June 14, 2022, by the journal JAMA (Journal of the American Medical Association). Read the abstract of “Association of Screening With Digital Breast Tomosynthesis vs Digital Mammography With Risk of Interval Invasive and Advanced Breast Cancer.”
About 3D mammograms
A 3D mammogram — also called digital breast tomosynthesis, digital tomosynthesis, or just tomosynthesis — creates a 3D picture of the breast using X-rays. Several images from different angles around the breast are used to create the 3D picture.
A traditional mammogram creates a 2D image of the breast from two X-ray images of each breast.
In 2011, 3D mammography was approved by the U.S. Food and Drug Administration (FDA) and later became a standard of care for breast cancer screening. Still, 3D mammography may not be available at all hospitals and mammogram facilities.
To start offering 3D mammograms, facilities must buy new mammography machines or update their existing machines to make them 3D-capable. Not all facilities have been able to make the switch to 3D mammography because of large up-front costs for equipment. In other cases, facilities that have rental agreements for 2D mammography equipment must wait until those leases end before they can upgrade.
According to statistics from the FDA from June 1, 2022, about 83% of U.S. screening facilities now offer 3D mammograms in at least one of their mammography units, but fewer than half of all accredited units are actually 3D-capable.
What is breast density and how is it measured?
Compared with breasts that aren’t dense, dense breasts have less fatty tissue and more gland tissue that makes and drains milk, and more supportive tissue (also called stroma) that surrounds the gland.
One way to measure breast density is by looking at the thickness of tissue on a mammogram. The BI-RADS (Breast Imaging Reporting and Database System), which reports the findings of mammograms, also includes information on breast density. BI-RADS classifies breast density into one of four groups:
scattered areas of density
Research has shown that dense breasts can:
be twice as likely to develop cancer as non-dense breasts
make it harder for mammograms to detect breast cancer because breast cancers (which look white like breast gland tissue) are easier to see on a mammogram when they’re surrounded by fatty tissue (which looks dark)
Nearly half the women ages 40 and older in the United States are considered to have dense breasts.
About the study
In this study, the researchers wanted to know if screening 3D mammograms could lower the risk of invasive interval breast cancers and advanced-stage breast cancers in women with dense breasts.
Interval breast cancers are cancers found in between regular screening mammograms.
The researchers looked at the results of 1,379,089 screening mammograms done on 504,427 women.
The women were ages 40 to 79 and had no history of breast cancer. The women had a 3D mammogram, a 2D digital mammogram, or both between January 2011 and December 2018.
308,141 women had only 2D digital mammograms, with an average of 2.2 mammograms per woman
56,939 women had only 3D mammograms, with an average of 1.6 per woman
139,347 women had both 2D digital and 3D mammograms, with an average of 2.3 2D digital mammograms and 2 3D mammograms per woman
Women who had 3D mammograms were more likely to:
have a first-degree relative — mother, sister, or daughter — with a history of breast cancer
have had a breast biopsy in the past
have a higher-than-average risk of breast cancer
Overall, about 3.6% of the women had extremely dense breasts and a very high risk of breast cancer.
The results showed interval breast cancer rates were not different between women who had 2D digital mammograms and women who had 3D mammograms, no matter their breast density.
Among women with extremely dense breasts and a high risk of breast cancer, women who had screening with 3D mammograms had a lower risk of advanced-stage breast cancer than women who had 2D digital mammograms.
“This study’s findings suggest for facilities with both [3D] and digital mammography available, triaging women with extremely dense breasts and at high risk to undergo [3D mammography] may be clinically indicated,” the researchers wrote.
What this means for you
If you have extremely dense breasts and a high risk of breast cancer, this study offers important information. If you aren’t sure whether your screening facility offers 3D mammograms, it’s a good idea to call and check before you make an appointment. If the facility doesn’t offer 3D mammograms, you may want to consider asking your doctor to recommend a facility that does.
In some states, such as Washington, there are laws that require facilities not to charge more for 3D mammograms than they do for 2D mammograms. So even if your health insurance doesn’t cover it, you can still get a 3D mammogram for the cost of a 2D mammogram, which in almost all states is free. In other states, such as New Jersey and Pennsylvania, there are laws that require health insurers to cover 3D mammograms at no cost to women.
You may want to call your health insurance provider to confirm whether your plan covers 3D mammograms. Both Medicare and Medicaid now cover 3D mammograms.
You also may want to call the facility to ask how much, if anything, you might have to pay for a 3D mammogram.
Written by: Jamie DePolo, senior editor
— Last updated on June 21, 2022, 9:37 PM